The subcutaneous adipose tissue is located at the hypodermis. It is a type of connective tissue where adipocytes are predominant, organized in lobes around 5 mm in diameter, separated by fine connective bridges. Each adipocyte contains a voluminous lipid vacuole containing essentially triglycerides and having a diameter that may range from 40 to 120 μm.
Adipose tissue may be considered to be a dynamic reservoir, constantly being renewed, balancing the dietary intake with the energy requirements of the body. Thus, adipocytes ensure the synthesis, accumulation and release of lipids. This process is dependent upon hormones such as insulin or leptin.
Lipid synthesis, or lipogenesis, originates with triglycerides of dietary origin and glucose. Conversely, the triglycerides stored in the adipocytes may be hydrolyzed, during lipolysis, to release fatty acids, glycerol and glycerol mono- and diesters.
The non-esterified fatty acids thus released may circulate in the blood and then be available for the energy requirements of other cells of the body, or be quickly reused by the adipocyte so as to generate, again, triglycerides by lipogenesis.
If a sustained imbalance occurs in the body promoting lipogenesis, the quantity of lipids stored in the adipocytes increases, leading to hyperplasia of the mass of body fat and more specifically to the appearance of localized excess body fat. In fact, in human adults, under the effect of sex hormones, the adipose tissue is distributed differently according to sex and forms the silhouette. Adipose tissue accumulates in the chest, on the hips, the buttocks and the thighs in women, and on the nape and shoulders in men. In addition, localized excess body fat is often associated with modifications in the skin, which develops a dimpled or “orange-peel” appearance. This localized excess body fat is currently considered to be unattractive, and people affected may want to improve the appearance of their skin and silhouette using cosmetic methods.
Numerous active agents having an action on lipolysis or lipogenesis, intended for slimming effect, have thus been identified. Among them, the following may be cited:                Xanthine bases (xanthine derivatives), such as theophylline, caffeine, theobromine (described in patents FR 2 609 395, FR 2 671 487), used for their action promoting the lipolytic activity of fat cells.        Synthetic peptides, such as the peptide of sequence Arg-Gly-Ser-NH2 (described in patent FR 2 858 769), or the peptide of sequence Pro-Leu-Asp-Thr-Ala-Lys-Val-Arg-Leu-Gln (described in patent FR 2 879 924) used for their action in the decoupling between coenzyme reoxidation and phosphorylation of ADP into ATP in the mitochondria.        Plant extracts, such as marine algae extract of the Palmaria or Rhodymenia genus (described in patent FR 2 887 447), gingko biloba extracts (see patent FR 2 669 537), or soy flavones or isoflavones (described in patent WO 01/64177).        
However, these products generally have moderate or limited efficacy over time. It is therefore important to provide new active cosmetic agents having remarkable efficacy as slimming active agents.
The solution to the technical problem addressed lies in the cosmetic use of the association of a carob germ extract and caffeine or a derivative thereof. The inventors have indeed demonstrated that a carob germ extract acts on aquaglyceroporins, thereby promoting the transport of glycerol released during lipolysis, from the adipocyte. The association of this extract with caffeine, or derivatives thereof, the latter already being known to increase lipolysis, makes it possible to obtain a slimming active agent having remarkable properties.
Aquaporins are a class of transmembrane proteins carrying water and small molecules in solution, between the cells and the internal medium. Aquaporins may be classified into two distinct sub-groups: aquaporins enabling only the transport of water, and aquaglyceroporins which enable, in addition to the transport of water, the transport of glycerol.
In this second sub-group, aquaglyceroporin 7 was identified in the membrane of human adipocytes and plays an important role in the metabolism of reserve fats (Mariko Hara-Chikuma et al. Progressive adipocyte hypertrophicity in aquaporin-7 deficient mice, J. Biol. Chem., vol. 280, no. 16, Apr. 22, 2005).
The particular properties of aquaglyceroporins therefore makes them beneficial biological targets for promoting the elimination of lipids contained in the adipocytes.
“Elimination of lipids” refers to the phenomenon of lipolysis leading to the export of glycerol from the adipocyte cell.
The invention and the resulting advantages will be better understood upon reading the description.